There are eleven expansions of Rudra, or Lord Siva. They are as follows: Ajaikapat, Ahibradhna, Virupaksa, Raivata, Hara, Bahurupa, Devasrestha Tryambaka, Savitra, Jayanta, Pinaki and Aparajita. Besides these expansions there are eight forms of Rudra called earth, water, fire, air, sky, the sun, the moon and soma-yaji. Generally all these Rudras have five faces, three eyes and ten arms. Sometimes it is found that Rudra is compared to Brahma and considered a living entity. But when Rudra is explained to be a partial expansion of the Supreme Personality of Godhead, he is compared to Sesa. Lord Siva is therefore simultaneously an expansion of Lord Visnu and, in his capacity for annihilating the creation, one of the living entities. As an expansion of Lord Visnu he is called Hara, and he is transcendental to the material qualities, but when he is in touch with tamo-guna he appears contaminated by the material modes of nature. This is explained in Srimad-Bhagavatam and the Brahma-samhita. In Srimad-Bhagavatam, Tenth Canto, it is stated that Lord Rudra is always associated with the material nature when she is in the neutral, unmanifested stage, but when the modes of material nature are agitated he associates with material nature from a distance. In the Brahma-samhita the relationship between Visnu and Lord Siva is compared to that of milk and yogurt. Milk is converted into yogurt by certain additives, but although milk and yogurt have the same ingredients, they have different functions. Similarly, Lord Siva is an expansion of Lord Visnu, yet because of his taking part in the annihilation of the cosmic manifestation, he is considered to be changed, like milk converted into yogurt. In the Puranas it is found that Durga appears sometimes from the heads of Brahma and sometimes from the heads of Visnu. The annihilator, Rudra, is born from Sankarsana and the ultimate fire to burn the whole creation. In the Vayu Purana there is a description of Sadasiva in one of the Vaikuntha planets. That Sadasiva is a direct expansion of Lord Krsna's form for pastimes. It is said that Sadasiva (Lord Sambhu) is an expansion from the Sadasiva in the Vaikuntha planets (Lord Visnu) and that his consort, Mahamaya, is an expansion of Ramadevi, or Laksmi. Mahamaya is the origin or birthplace of material nature.